An electric powertrain typically includes one or more high-voltage electric machines. Each electric machine is powered by a high-voltage battery pack or other suitable direct current (DC) device. In some configurations, a power inverter receives a DC output voltage from the battery pack and generates an alternating current (AC) voltage suitable for energizing the phase windings of the electric machines. The battery pack may be recharged as needed by connecting a charge coupler to a wall outlet, charging station, or other available offboard power supply via an electrical cable.
An AC-DC converter is used to convert an AC charging voltage into a DC output voltage suitable for storage in the various cells of the battery pack. Alternatively, a DC fast-charging system, also known as DC Quick Charger (DCQC), may be used to expedite the charging process. In such a configuration, the AC-DC converter is eliminated in favor of a junction box having high-voltage relays that close during charging to enable a charging current to pass from the charge coupler to the battery pack. Communication between the charging station/charging infrastructure and any electrical system-side charging equipment is achieved via a charging protocol, e.g., SAE J1772 in an example electric vehicle charging operation.
High-voltage charging architectures in vehicles and other systems typically include a number of power electronic components such as charge couplers, receptacles, electrical connectors, contactors, relays, fuses, and voltage bus bars. As is well known in the art, such components are typically current-limited or voltage-limited by the manufacturer to a particular temperature-based level. For each component, a corresponding steady-state charging current may be maintained indefinitely at a given component temperature. The power limit that is enforced during the battery charging process is typically controlled to the lowest steady-state limit of the various components of the electrical system.